It's not a pleasant scene, as you might imagine, so proceed with caution if you wish to watch. Campbell, who describes himself as an anarchist, can be heard asking "is this OK?" several times, apparently to check with the officers on whether he could keep moving past them as he filmed. At about the 32-second mark, the projectile is fired. It hits Campbell in the thigh and he goes down. He tells the Oakland Tribunethat he was "just stunned, and in an immense amount of pain," and has some swelling and brusing.

The department is investigating, officer Johanna Watson, a spokeswoman, tells the AP.

And, as the San Francisco Chronicle's Crime Scene blog reports, Oakland police have released some videos of their own "that they say show dozens of Occupy Oakland protesters threatening police the evening of Oct. 25."

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